Nondiagnostic 99mTc-MAG3 Diuresis Renography Studies Caused by Propofol Sedation: A Case Series.

ABSTRACT: 99mTc-MAG3 diuresis renography is a noninvasive functional imaging technique used to assess clearance of radiotracer in a dilated urinary tract under high diuresis. It is commonly performed in patients to diagnose functionally significant urinary tract obstruction. In some pediatric patients, sedation is required to enable imaging. However, propofol, a commonly used IV sedative agent, is associated with altered renal hemodynamics. We report a case series of 3 pediatric patients at our institution who received propofol sedation to enable 99mTc-MAG3 diuresis renography using a F+0 protocol, outlining that some "abnormal" studies were in fact assessed to be nondiagnostic.

Cystatin C kidney functional reserve: a simple method to predict outcome in chronic kidney disease.

BACKGROUND: Kidney functional reserve (KFR), the only clinical kidney stress test, is not routinely measured because the complexity of measurement has limited clinical application. We investigated the utility of plasma cystatin C (CysC) after oral protein loading (PL) to determine KFR in Stages 3 and 4 chronic kidney disease (CKD). METHODS: Following a 24-h low-protein diet, KFR was measured after oral protein by hourly plasma CysC and compared with simultaneous creatinine clearance (CrCl) and radionuclide 99technetium diethylenetriaminepentaacetatic acid (Tc-99m-DTPA) measured glomerular filtration rate (mGFR) measurement in an observational, single-centre cohort study of adults with CKD Stages 3 and 4. Subjects were followed for 3 years for fast (F) or slow (S) CKD progression, dialysis requirement or death or a combination of major adverse kidney events (MAKEs). RESULT: CysC, CrCl and Tc-99m-DTPA mGFR measurements of KFR in 19 CKD Stage 3 and 21 CKD Stage 4 patients yielded good agreement. KFR was not correlated with baseline kidney function. Eight CKD Stage 3 (42%) and 11 CKD Stage 4 (52%) subjects reached their lowest serum CysC concentration 4 h after PL. CysC KFR and baseline serum creatinine (sCr) predicted death or dialysis or MAKE-F with a respective area under the curve (AUC) of 0.73 [95% confidence interval (CI) 0.48-0.89] and 0.71 (95% CI 0.51-0.84). Including CysC KFR, age, baseline sCr and nadir CysC predicted a decrease in sCr-estimated GFR >1.2 mL/min/year (MAKE-S) with an AUC of 0.89. CONCLUSIONS: Serial CysC avoided timed urine collection and radionuclide exposure and yielded equivalent estimates of KFR. Serial CysC may facilitate monitoring of KFR in clinical practice.

Triple-site radiotracer application in breast lymphoscintigraphy and sentinel node discordance.

Sentinel lymph node (SLN) biopsy (SLNB) has demonstrated accuracy in the axillary staging of breast cancer patients. Despite variability in selection criteria and technique, an SLN is consistently identified in approximately 96% of cases and in most series predicts the status of remaining axillary LNs in >95% of cases. The false-negative rate of sentinel lymph node biopsy (SLNB) was originally reported as 5%-10% (sensitivity 90%-95%), but improved rates are attainable by experienced surgeons. Radiolocalization with lymphoscintigraphy (LSG) increases SLN identification rates. LSG is a useful tool to establish the abnormal lymphatic drainage patterns and to detect the extra-axillary nodes, particularly internal mammary nodes. Despite controversy regarding the optimal injection method, studies have generally suggested high concordance between the various radiotracer application sites and axillary SLN identification. Discordant SLN identification would have implications for nodal staging as the true SLN might not be identified with individual injection techniques. In the current study, imaging from consecutive patients presenting for breast LSG over a-19 month period was retrospectively reviewed. Radiotracer application was performed with simultaneous injection of peritumoral, subcutaneous, and subareolar regions. This application method provided a mechanism to assess the LSG drainage patterns with a view to assessing injection site concordance and SLN identification rates. Data from 123 breast LSG patients were reviewed. Using our radiotracer technique, the axillary SLN identification rate was 98%. A single axillary node was detected in 110, two axillary nodes were detected in 10, and no axillary node was detected in three patients. Among those 10 patients in whom two axillary nodes were seen, at least two cases of discordant drainage occurred from different injection sites. This study demonstrates that different LSG injection sites can result in the identification of different axillary sentinel nodes although this appears to be a rare event. This finding may be of clinical importance if the true SLN is sought. In addition, the multisite injection technique appears to be an optimal method of axillary SLN identification, with high SLN detection rates.

Lymphoscintigraphic SPECT/CT-Contralateral Axillary Sentinel Lymph Node Drainage in Breast Cancer.

A 58-year-old woman with previous right breast carcinoma treated with lumpectomy, right axillary clearance, chemo-radiotherapy, and adjuvant hormonal therapy underwent a lymphoscintigraphy for a new right breast lesion. On planar images, an alternate route of lymphatic drainage was observed to the right internal mammary chain and the left axilla. A chest SPECT/CT was performed to confirm the location of the sentinel nodes. The patient underwent a right mastectomy and left axillary sentinel lymph node biopsy, which showed no evidence of lymphovascular invasion. Combining planar imaging and SPECT/CT techniques can accurately identify sentinel lymph nodes at their new unpredicted location.

The relative function of damaged kidneys in children does not deteriorate further at 3-year follow-up.

PURPOSE: It is thought that the function of a damaged kidney will deteriorate further with time because of impaired maturation and compensatory hyperfiltration. The aim of this study was to determine changes in relative renal function (RRF) over time in children with vesicoureteric reflux (VUR) and/or urinary tract infection (UTI) where the unilaterally scarred kidney was found to contribute 30% or less to overall function. PATIENTS AND METHODS: Children who met the inclusion criteria and had multiple radionuclide studies during a 12-year period were identified, and RRF was compared. RESULTS: Twenty-seven boys and 3 girls with a median age of 0.8 years (0.08-13.05 years) were included. Eight patients had unilateral VUR, 21 patients had bilateral VUR, and 1 patient had UTIs without VUR. Twenty-one patients underwent reimplantation surgery, and 9 were managed conservatively.At a mean follow-up of 2.64 years (0.26-6.77 years), there was a nonsignificant mean decrease in RRF from 19% (11%-28%) to 18% (9%-29%). The mean change in renal function was not affected by the severity of the initial RRF. CONCLUSIONS: In the medium term, there is no deterioration of RRF of unilaterally severely damaged kidneys associated with either VUR or UTI managed either surgically or conservatively. Boys are at a much greater risk of severe reflux nephropathy.

2-deoxy-2-((18)F)fluoro-D-glucose positron emission tomography/computed tomography imaging in paediatric oncology.

Positron emission tomography (PET) is a minimally invasive technique which has been well validated for the diagnosis, staging, monitoring of response to therapy, and disease surveillance of adult oncology patients. Traditionally the value of PET and PET/computed tomography (CT) hybrid imaging has been less clearly defined for paediatric oncology. However recent evidence has emerged regarding the diagnostic utility of these modalities, and they are becoming increasingly important tools in the evaluation and monitoring of children with known or suspected malignant disease. Important indications for 2-deoxy-2-((18)F)fluoro-D-glucose (FDG) PET in paediatric oncology include lymphoma, brain tumours, sarcoma, neuroblastoma, Langerhans cell histiocytosis, urogenital tumours and neurofibromatosis type I. This article aims to review current evidence for the use of FDG PET and PET/CT in these indications. Attention will also be given to technical and logistical issues, the description of common imaging pitfalls, and dosimetric concerns as they relate to paediatric oncology.

False-positive MIBG uptake in pneumonia in a patient with stage IV neuroblastoma.

A 32-month-old female child with a history of stage IV favorable biology neuroblastoma with a 123-I MIBG (metaiodobenzylguanidine scan) avid adrenal mass, with retroperitoneal nodal extension and bony metastasis, was in complete remission after intense multimodal therapy. Seventeen months after diagnosis a surveillance 123-I MIBG scan showed abnormal tracer uptake in the midzone of the right thorax. Chest x-ray and CT scan confirmed right upper lobe consolidation corresponding to the tracer uptake. Chest x-ray after antibiotics showed resolution of the abnormality. 123-I MIBG scan 3 months later showed no abnormal uptake. False-positive MIBG uptake in pneumonia has not been previously reported.

Treatment of fluorouracil-refractory patients with liver metastases from colorectal cancer by using yttrium-90 resin microspheres plus concomitant systemic irinotecan chemotherapy.

PURPOSE: Liver metastases are the principal cause of death in patients with advanced colorectal cancer (CRC). Irinotecan is a chemotherapeutic agent used in the treatment of CRC and has demonstrated synergistic potential when used with radiation. Radioembolization with yttrium-90 microspheres has demonstrated increased response and survival rates when given with fluorouracil chemotherapy. This study's goal was to evaluate the maximum-tolerated dose of concomitant irinotecan and radioembolization in fluorouracil-refractory patients with CRC hepatic metastases. PATIENTS AND METHODS: Twenty-five irinotecan-naive patients who had experienced relapse after previous chemotherapy were enrolled onto three dose-escalating groups. Irinotecan was administered at 50, 75, or 100 mg/m(2) on days 1 and 8 of a 3-week cycle for the first two cycles, and full irinotecan doses (ie, 100 mg/m(2)) were administered during cycles 3 to 9. Radioembolization was administered during the first chemotherapy cycle. RESULTS: Most patients experienced acute, self-limiting abdominal pain and nausea. Mild lethargy and anorexia were common. Grades 3 to 4 events were seen in three of six patients at 50 mg/m(2) (obstructive jaundice, thrombocytopenia, diarrhea), in five of 13 patients at 75 mg/m(2) (neutropenia, leukopenia, thrombocytopenia, elevated alkaline phosphatase, abdominal pain, ascites, fatigue) and in four of six patients at 100 mg/m(2) (diarrhea, deep vein thrombosis, constipation, leukopenia). Eleven (48%) of 23 patients had a partial response, and nine patients (39%) had stable disease. The median progression-free survival was 6.0 months; the median survival was 12.2 months. CONCLUSION: Concomitant use of radioembolization plus irinotecan did not reach a maximum-tolerated dose. The recommended dose of irinotecan in this setting is 100 mg/m(2) on days 1 and 8 of a 3-week cycle.

Renal infection and vesico-ureteric reflux.

Urinary tract infection (UTI) is a common disease of childhood. The investigation of UTI in children has been the subject of debate and controversy for many years. Most workers agree that the first imaging modality to be used should be an ultrasound examination to exclude obstruction, structural abnormalities, and renal calculi. The role of (99m)Tc dimercaptosuccinic acid scintigraphy (DMSA) in the diagnosis of acute pyelonephritis is becoming increasingly important. Many argue that if the DMSA study is normal at the time of acute UTI, no further investigation is required because the kidneys have not been involved and thus there will be no late sequelae. Others use the acute DMSA study to determine the intensity of antibiotic therapy. The importance of the role of vesico-ureteric reflux (VUR) is being debated. Some workers will only proceed to cystography to detect VUR if the DMSA study is abnormal, whereas others advocate a more aggressive approach. VUR can be identified by a variety of radiological and scintigraphic techniques. Although the radiological cystogram is the gold standard and is essential in the first UTI in a male patient, to exclude the presence of posterior urethral valves, radionuclide cystograms are advantageous in other situations. Suprapubic cystography techniques have been described to overcome the trauma of urethral catheterization but have not been widely accepted.

Dural metastasis demonstrated on Tc-99m MDP bone scintigraphy in staging workup for a patient with breast cancer.

An 80-year-old woman with multifocal invasive lobular carcinoma of the right breast treated 6 years previously with mastectomy, locoregional radiotherapy, and tamoxifen was referred for a bone scan to investigate generalized arthralgias. The patient reported right-sided headaches, blurred vision, and dizziness in the previous 3 months. The bone scan revealed a large area of unusual and abnormal Tc-99m methylene diphosphonate (MDP) uptake in the right frontoparietal skull region. CT and MRI of the brain were performed to evaluate the possibility of cerebral metastases. The CT revealed extensive abnormal thickening and enhancement of the dura in the right frontoparietal region. No calcification of the dura or bony destruction of the overlying skull was evident on CT. MRI similarly revealed extensive thickening and irregularity of the dura. The usual causes of increased skull Tc-99m MDP uptake on bone scanning such as skull metastases and dural calcification were not evident on CT or MRI.

Gastrointestinal stromal tumours: correlation of F-FDG gamma camera-based coincidence positron emission tomography with CT for the assessment of treatment response--an AGITG study.

BACKGROUND: Malignant gastrointestinal stromal tumours (GISTs) are a rare subset of aggressive mesenchymal tumours specific to the gastrointestinal system. They are both locally aggressive and can metastasize. The aim of this analysis was to report on our experience of the utility of coincidence positron emission tomography (co-PET) based on an 18F-FDG gamma camera in assessing treatment response to imatinib using CT as the comparator and the final clinical outcome as the end point. METHODS: We compared the results of CT and PET scans as predictors of outcome in a consecutive series of patients treated at the Prince of Wales hospital. All patients had biopsy-proven malignant GIST and were on treatment with the targeted pharmacotherapeutic agent imatinib. The majority of the patients were receiving treatment as part of the randomized trial of the European Organization for Research and Treatment of Cancer, the Australian Gastrointestinal Trials Group and the Italian Sarcoma Group, comparing 400 with 800 mg (400 mg b.i.d.). The monitoring of tumour response was achieved by serial CT measurements according to the RECIST criteria. Concurrent 18F-FDG co-PET studies were performed within a mean of 2.8 days from the CT scan and were interpreted by a consensus panel of 2 nuclear medicine physicians. RESULTS: A total of 18 patients were recruited into the study, with a total of 74 lesions. There were 47 liver lesions, 31 of which were identified on the initial 18F-FDG co-PET scans (63%). There were 10 primary lesions (4 stomach, 4 duodenal, 2 small bowel), 9 of which were demonstrated on initial 18F-FDG co-PET examinations (90%). There were 17 extrahepatic metastatic sites, 15 of which were visualized on the initial 18F-FDG study (88%). Of the 18 patients, 8 showed concordant improvement on both CT and (18)F-FDG co-PET criteria. One patient showed concordant worsening and 1 was not FDG avid. Eight patients initially showed discordance. 18F-FDG co-PET studies demonstrated changes preceding CT findings in all 8 patients with subsequent concordant improvement. CONCLUSION: 18F-FDG co-PET is a useful modality to monitor treatment response to imatinib in patients with malignant GIST. Although there is a relatively reduced sensitivity when compared with CT for the detection of lesions especially in the liver, co-PET changes in several instances precede the changes on CT scanning. This modality has the potential to influence clinical decision making and should be considered as part of the standard care of patients on imatinib.

Renal scintigraphy unraveled the diagnostic dilemma of antenatal hydronephrotic solitary kidney-crossed renal ectopia.

On antenatal ultrasound assessment, an apparently solitary hydronephrotic kidney was identified, confirmed on postnatal ultrasound examination. More detailed postnatal investigations revealed the diagnosis of crossed renal ectopia.